The purpose of this study is to assess the safety and efficacy of 30 mcg/kg/ day single subcutaneous injection of growth hormone releasing hormone or growth hormone releasing factor (GRF 1-29) NH2, in the treatment of growth failure in previously untreated prepubertal children with a deficiency of pituitary growth hormone of unknown origin. This is an open, non-comparative, multinational study involving 60 evaluable (80 enrolled) patients.